What ratio should I use for an acrylic wash?

A typical acrylic wash uses a ratio of about 3:1 to 5:1 (water/medium to paint). For a light, transparent wash, go to 10:1. For a more opaque wash with visible brush strokes, stay around 2:1. Adding a flow medium instead of pure water helps maintain paint film integrity.

Can I thin acrylic paint with just water?

You can thin acrylics with water up to about 30% (roughly 1:3 water to paint ratio) without problems. Beyond that, the paint film becomes weak and may crack or not adhere properly. For thinner applications, use an acrylic medium or flow improver instead of pure water.

What is the fat over lean rule for oil painting?

Fat over lean means each successive layer of oil paint should contain more oil (fat) than the layer below. This prevents cracking as the painting dries. Start with more turpentine and less oil in lower layers, gradually increasing the oil content in upper layers.

ArtCalcs

Paint Dilution Calculator — Paint to Thinner Ratios

Calculate the correct ratio of paint to thinner or medium for washes, glazes and fluid techniques.

Total Volume Needed

Total mixed volume

Ratio Preset

How We Calculate This

This calculator splits a total volume into paint and thinner portions based on your chosen ratio.

Paint volume = (Paint parts / Total parts) × Total volume

Thinner volume = (Thinner parts / Total parts) × Total volume

Common dilution ratios (paint:thinner)

1:1 — Medium consistency, good for general painting
1:2 — Slightly thinned, smoother flow
1:3 — Fluid wash for transparent effects
1:5 to 1:10 — Very thin glazes and staining techniques

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.